Trying to find source of motion of a bone in blender 2.8
You've created some actions then pushed them down from the Dopesheet into the NLA, so they are playing in the NLA and you don't see them in the Dopesheet for the moment, it's the NLA that is playing. If you want to see one of these actions again in the Dopesheet you need to go in the NLA, select a strip and press tab, it will appear in the Dopesheet, or you can also reload it directly in the Dopesheet / Action Editor mode: Select its name in the dropdown menu of the horizontal menu bar.